I'm looking for answers to my mysterious knock sensor code on my 2001 LS430 180k miles. P0325 Knock sensor circuit 1 is the code I am recieving. Trying to do some preventative maintenance I changed the spark plugs with NGK laser iridium. Prior spark plugs I believe were the Densos. I as well changed a leaky PCV hose and went ahead and did the valve. The car ran great for roughly a week or so and then the code came and hasn't left. I seafoamed the car as well after getting the code. If I reset the code the car runs great, but returns shortly. I notice a slight tick and pinging under hard acceleration. Any suggestion would greatly be appreciated! I changed the spark plugs again also hoping maybe one of the NGK's was gapped incorrectly. I've went over the harnesses looking for shorts. It just seems strange I change the spark plugs and a knock sensor decides to give out.